Borage contains mucous substances, tannins, saponins, resins, essential oil, potassium, calcium, vitamin C and other substances.
The borage leaves contain small amounts of pyrrolizidine alkaloids found to be toxic to the liver. However, the levels of those toxic alkaloids are extremely low.
The oil from the seeds is rich in gamma-linolenic acid (GLA), an omega-6 fatty acid. The amount of GLA in the oil ranges from 20 to 27 percent.
The oil also contains about 10 percent alpha-linolenic acid (ALA), an omega-3 fatty acid.
The herb has been used traditionally as an herbal remedy to treat urinary tract infections, cystitis, chronic kidney inflammation, catarrh, pneumonia, tuberculosis, gastritis, irritable bowel syndrome and depression.
As a mouthwash, it is used to treat mouth and throat infections, mouth ulcers and bleeding gums.
The oil from the seeds is an alternative to evening primrose oil for atherosclerosis, rheumatic pain, premenstrual syndrome (PMS), menstrual problems, prostate disorders, allergies, arthritis, eczema and other skin problems.